hd66765 Renesas Electronics Corporation., hd66765 Datasheet - Page 49

• Manufacturer Part Number: hd66765
• Description: 396-channel Segment Driver With Internal Ram For 4096-color Displays - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

Logical/Compare Operation Function
The HD66765 performs a logical operation or conditional replacement between the two-byte write data
sent from the microcomputer and the read data from the GRAM. The logical operation function has four
types: replacement, OR, AND, and EOR. The conditional replacement performs a compare operation for
the set value of the compare register (CP11–0) and the read data value from the GRAM, and rewrites
only the pixel data in the GRAM that satisfies the conditions (in a byte unit). This function can be used
when a particular color is selectively rewritten. The swap function or write-data mask function can be
effectively used.
Table 24
Bit Setting
LG2
0
0
0
0
1
1
1
1
LG1
0
0
1
1
0
0
1
1
Logical/Compare Operation
LG0
0
1
0
1
0
1
0
1
Description of Logical/Compare Operation Function
Writes the data written from the microcomputer directly to the GRAM. Only
write processing is performed since the data in the read-data latch is not used.
ORs the data in the read-data latch and the data written by the microcomputer.
Writes the result to GRAM. Read, modify, or write processing is performed.
ANDs the data in the read-data latch and the data written by the
microcomputer. Writes the result to GRAM.
EORs the data in the read-data latch and the data written by the
microcomputer. Writes the result to GRAM.
Compares the data in the read-data latch and the set value of the compare
register (CP11–0). When the read data matches CP11–0, the data from the
microcomputer is written to the GRAM. Only the particular color specified in
the compare register can be rewritten. Read, modify, or write processing is
performed.
Compares the data in the read-data latch and the set value of the compare
register (CP11–0). When the read data does not match CP11–0, the data from
the microcomputer is written to the GRAM. Colors other than the particular
one specified in the compare register can be rewritten. Read, modify, or write
processing is performed.
Compares the data written to the GRAM by the microcomputer and the set
value of the compare register (CP11–0). When the write data matches
CP11–0, the data from the microcomputer is written to the GRAM. Only write
processing is performed.
Compares the data written to the GRAM by the microcomputer and the set
value of the compare register (CP11–0). When the write data does not match
CP11–0, the data from the microcomputer is written to the GRAM. Only write
processing is performed.
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HD66765